玉米和豆科植物单播及混播对弱碱性土壤中重金属的植物提取效果研究

发布时间：2018-05-02 22:11

本文选题：植物提取 + 重金属　；参考：《兰州大学》2015年硕士论文

【摘要】：农田土壤重金属污染是一个世界性的问题,并有不断恶化的趋势。农田土壤重金属污染不仅会使作物受到重金属毒害而导致产量下降,还可能在作物中富集,对食用人群健康产生风险。因此,开展污染农田土壤监测与修复研究迫在眉睫。白银东大沟农业区由于长期污灌的原因,弱碱性农田土壤中受到了以Cu、Zn、Pb和Cd为主的重金属污染。本研究以白银市四龙镇梁庄村为研究样地,选择单播玉米(Zea mays)为种植方式,研究不同时期(三叶期(vegetative stage with three leaves, V3)、六叶期(vegetative stage with six leaves, V6)、八叶期(vegetative stage with eight leaves, V8)、十二叶期(vegetative stage with twelve leaves, V12)、抽穗期(tasseling of the vegetative stage, VT)、抽丝期(silking of the reproductive stage, R1)、发泡期(blistering of the reproductive stage, R2)、乳熟期(doughing of the reproductive stage, R4)和生理成熟期(physiological maturity of the reproductive stage, R6))玉米提取重金属的动态过程,并比较玉米、大豆(Glycine max)、豌豆(Pisum sativum)、苜蓿(Medicago sativa)单播及玉米与上述豆科植物混播对土壤重金属的移除效果。研究工作主要取得以下结果：1.单播玉米(monocropping maize, MM)提取和转移重金属主要依赖蒸腾作用。研究发现,在整个生长过程中,老叶中始终含有较高浓度的重金属,而籽粒中含有的重金属浓度是最低的,说明重金属进入植物体后不易随有机营养物质的运输而发生转移；而茎和叶这些可以进行光合作用并富含气孔的器官中含有高浓度的重金属则说明了植物提取重金属的动力主要是蒸腾作用。2.玉米R6期为最佳重金属提取时期。MM对重金属的提取随着积温的积累在营养生长阶段的前期缓慢增加,在营养生长后期至生殖生长前期进入一个对数增长的时期,而在生殖生长末期其增长速率下降甚至停滞,非线性拟合数据也表明S型增长模型最适合模拟玉米对重金属的提取。在R6期,玉米具有最大的生物量、相对较低的重金属浓度和较高的重金属提取量,因此本研究选取生理成熟期作为比较不同种植方式下重金属提取效率及植物生物量利用的时期。3.单播与混播方式的生物量产出无显著差异,而玉米与大豆混播(maize-soybean intercropping, IS)对土壤重金属的提取效果要优于MM。玉米与大豆、豌豆及苜蓿混播与MM相比,生物量无显著差异。而且,IS显著提高了对重金属Cu、Zn的提取量。这说明本研究采用的种植模式可以在不影响生物量产出的情况下提高对土壤重金属的移除效果。此外,所产出的植物生物量中重金属浓度均低于饲料中重金属的标准限值,因此可以将产出生物量作为青储饲料加以利用。4.植物的根际活动会引起根系土中重金属的活化,这一现象可将重金属植物提取的效率维持在较高的水平,且不会增加深层土壤重金属的生态风险。不同处理组中土壤重金属总量并无显著差别,二乙烯三胺五乙酸(diethylenetriamine pentaacetic acid, DTPA)可提取态重金属含量在大多数的根系土中都显著高于非根系土,这一现象说明植物根系对土壤重金属的活化。土壤重金属的活化可以使植物对土壤重金属的提取效率维持在较为稳定的水平,但同时也会提高土壤重金属下渗进而影响地下水或地表水的可能。因此,本研究还检测了单播大豆(monocropping soybean, MS)根系和非根系区域的不同深度土壤中重金属的DTPA态重金属含量,结果表明大豆根际活动引起的DTPA可提取态重金属含量升高对深层土壤无显著影响,仅引起40-60cm深处根系土中的DTPA可提取态的Zn和Cd浓度显著升高。因此,MS对深层土壤的重金属影响很小,可推测出对Zn和Cd活化程度较低的IS对深层土壤的重金属影响较小,可以放心采用。总之,在玉米R6期收获玉米可以获得重金属浓度较低而重金属提取量较高的生物量；IS可以在不减少生物量产出的前提下,提高对Zn、Cd的提取量；植物根际对土壤重金属的活化作用可在不影响地下水的前提下,使植物对土壤重金属的植物提取效率维持在一个稳定的水平。根据以上研究结论,本文认为采取恰当的种植方式可保证白银地区作物的安全,从而减少对当地消费者(人及家畜)产生的健康风险。
[Abstract]:Heavy metal pollution in farmland soil is a worldwide problem and has a tendency to deteriorate. Heavy metal pollution in farmland soil will not only cause the crops to be poisoned by heavy metals, but also may be enriched in crops and risk the health of edible people. Therefore, it is imminent to carry out the research on soil monitoring and remediation of contaminated farmland. The soil of weak alkali farmland is polluted by Cu, Zn, Pb and Cd in the agricultural area of Baiyin dongdigu agricultural area. This study takes Liang Zhuang village of four Dragon Town, Baiyin as the research sample, and chooses the single seed maize (Zea mays) as the planting mode, and studies the three leaf stage (vegetative stage with three leaves, V3), six Vegetative stage with six leaves (V6), the eight leaf stage (vegetative stage with eight leaves, V8). The dynamic process of heavy metal extraction from maize, doughing of the reproductive stage, R4 and physiological maturity (physiological maturity of the reproductive stage), and a comparison of maize, soybean, pea, alfalfa and maize with the above leguminous plants The main results of the study are as follows: 1. monocropping maize (MM) extraction and transfer of heavy metals mainly depend on transpiration. It is found that in the whole growth process, the heavy metals in the old leaves are always high, and the concentration of heavy metals in the grain is the lowest, indicating the entry of heavy metals. The plant body is not easy to transfer with the transport of organic nutrients, and the stems and leaves, which can carry on Photosynthesis and contain high concentrations of heavy metals in the organs rich in stomata, indicate that the main motive force of the plant extraction of heavy metals is the transpiration of.2. maize R6 period as the extraction of heavy metals by.MM during the optimum extraction period of heavy gold. Accumulation of accumulated temperature slowly increased at the early stage of the vegetative growth stage, and entered a logarithmic growth period from the late vegetative growth stage to the procreation prophase, and the growth rate decreased or even stagnated at the end of reproductive growth. The nonlinear fitting data also indicated that the S model growth model was the most suitable for the extraction of heavy metals from simulated maize. In the R6 period, the corn was used as a model. With the maximum biomass, relatively low heavy metal concentration and high heavy metal extraction, there was no significant difference in biomass yield between.3. mono sowing and mixed sowing of heavy metal extraction efficiency and plant biomass utilization in this study, while maize and soybean mixed sowing (maize-soyb The effect of EAN intercropping, IS) on the extraction of heavy metals in soil is better than that of MM. corn and soybean, and there is no significant difference in biomass between the mixed sowing of pea and alfalfa and MM. Moreover, IS significantly improves the extraction of heavy metal Cu and Zn. This shows that the planting pattern adopted in this study can improve the soil weight without affecting the biomass output. In addition, the heavy metal concentration in the plant biomass is lower than the standard limit of heavy metals in the feed, so the output biomass can be used as a green storage feed to use the rhizosphere activity of the.4. plant to cause the activation of heavy metals in the root soil. This phenomenon can maintain the efficiency of the extraction of heavy metal plants. There was no significant increase in the ecological risk of heavy metals in deep soil. There was no significant difference in the amount of heavy metals in soil. Two ethylene three amine five acetic acid (diethylenetriamine pentaacetic acid, DTPA) content of the extractable heavy metals in most of the root soil was significantly higher than that in the non root soil. The activation of heavy metals in soil was activated by roots. The activation of heavy metals in the soil could maintain a stable level of the extraction efficiency of heavy metals in the soil, but it also increased the possibility of infiltration of heavy metals under the soil and the potential of surface water. Therefore, this study also examined the roots of monocropping soybean (MS) and the roots of soybean. The content of heavy metals in DTPA state in different depth soils of non root region showed that the increase of DTPA extractable heavy metal content caused by soybean rhizosphere activity had no significant effect on deep soil. The concentration of Zn and Cd in the extracted state of DTPA in root soil of 40-60cm depth increased significantly. Therefore, MS was used to the heavy metals in deep soil. The influence is very small, it can be deduced that the IS with low activation degree of Zn and Cd has little influence on the heavy metals in deep soil, and can be used safely. In a word, the biomass of heavy metal concentration is lower and the heavy metal extraction is higher in the maize harvest period of Maize. IS can improve the extraction of Zn and Cd without reducing the yield of raw materials. The activation of Plant Rhizosphere on soil heavy metals can maintain a stable level of plant extraction efficiency of heavy metals in the soil without affecting the ground water. According to the above conclusions, this paper holds that appropriate planting methods can ensure the safety of the crops in the silver region, thus reducing the local consumers (people). Health risks associated with livestock.

【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53;X173

【共引文献】